With the advancement of technology and the development of economic, the demand switching converter increases. In recent years, because the significant advances in power electronic technology and the trend to thin and light, the power converter in switching converter is also required to have thin and light design. Thus, in recent years, the switching power converters with thin and light design have gradually replace the conventional linear power converters and become the main trend of power converters. In addition, besides having the thin and light features, the switching converter also improve the efficiency and quality of converters.
Basically, power factor corrector (PFC) can be operated in continuous conduction mode (CCM) or discontinuous conduction mode (DCM). For low-power systems, generally the power factor correctors adopt the discontinuous conduction mode to control the switching mode. On the contrary, for high-power systems, generally the power factor correctors adopt the continuous conduction mode.
In general, when a conventional boost converter in continuous conduction mode has a hard switching, some power may be lost when the power switch is OFF and ON due to the voltage and current delays in the instantaneous moment of OFF and ON; wherein the power loss is so-called switching loss. Basically, the switching loss issue can be solved by using external circuit to make the voltage and current have phase interlacing shifts.